Solar photovoltaic (PV) conversion devices are an increasingly important source of electricity. The basic PV building block is a PV cell, a semiconductor device which converts light energy into electric current. In common practice, PV cells are connected electrically in series and physically encapsulated in a protective assembly to form PV modules, each of which is typically on the order of 1 square meter in aperture area. PV modules are in turn connected electrically in series and assembled physically into an array. The electrical output of the array is typically connected to an inverter, which converts the DC output of the PV array to AC for use.
PV cells (and thus PV modules and PV arrays) exhibit a nonlinear relationship between terminal voltage and current. The load impedance that is applied to the PV array must be dynamically adjusted in order to extract the maximum possible power from the array, in a process known as Maximum Powerpoint Tracking (MPPT).